Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8187096 | Physics Letters B | 2018 | 8 Pages |
Abstract
The Zâ²-gauge boson in an U(1)LμâLÏ gauge symmetry has two interesting features: one is its vector couplings to the charged leptons, and the other is the decoupling from the electron. Based on these properties, we investigate the feasibility to simultaneously resolve the RK(â)=BR(BâK(â)μ+μâ)/BR(BâK(â)e+eâ) and RD(â)=BR(B¯âD(â)Ïν¯Ï)/BR(B¯âD(â)âν¯â) anomalies in an U(1)LμâLÏ model, where the former is expected to arise from the Zâ²-penguin-induced bâsμ+μâ process and the latter from the tree-level bâcÏÎ½Â¯Ï decay. In order to achieve the intended purpose, we employ one vector-like doublet lepton and one singlet scalar leptoquark (LQ), in which the new particles all carry the U(1)LμâLÏ charges; the bâsZâ² effective interaction is generated from the vector-like lepton and LQ loop, and the bâcÏÎ½Â¯Ï decay is induced from the LQ. When the constraints from the bâsγ, B+âK+νν¯, BcââÏν¯Ï, ÎF=2, and Ïâμâ⯠processes are included, it is found that RD and RDâ can be enhanced to fit the experimental data, and the Wilson coefficient C9 from the LQ-loop can reach C9LQ,μâ¼â1, which can explain the RK and RKâ anomalies. In addition, in this simple model, the Higgs lepton-flavor violating hâÎ¼Ï decay can occur at the tree level, and its branching ratio can be as large as the current experimental upper limit.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Nuclear and High Energy Physics
Authors
Chuan-Hung Chen, Takaaki Nomura,